Network-provided content, such as Internet web pages and the like, are typically served to end users via networked computer systems. End user requests for network content are processed and the content is responsively provided over various network links. These networked computer systems can include origin or hosting servers that originally host network content, such as web servers for hosting a news website. However, computer systems consisting solely of individual content origins or hosts can become overloaded and slow due to frequent requests of content by end users.
Content delivery networks (CDNs) add a layer of caching between content providers' original servers and end users. Content delivery networks typically have multiple distributed edge cache nodes that provide end users with faster access to content. When an end user requests content, such as a web page, the request is handled by an edge cache node that is configured to respond to the end user request (e.g., instead of an origin server). Specifically, when an end user directs a content request to a given origin server, the domain name system (DNS) resolves to an edge cache node (frequently the edge node is selected as an optimized server) instead of the origin server and the edge cache node handles that request.
Thus an edge cache node acts as a proxy or cache for one or more origin servers. Various types of origin server content can be cached in the content delivery network's various cache nodes. When all or a portion of the requested content has not been cached by an edge cache node, that edge cache node typically requests the relevant content (or portion thereof) from the appropriate origin server(s) on behalf of the end user.